The Intruder [H.m.verrucosus

[alexander]

I always thought that the little frogs we get in our garden were Arum Lily Reed Frogs such as the one below (from my garden).


But today i noticed 2 others "sunning" themselves, and the brighlty coloured one was definately Painted Reed Frog (H.m.verrucosus). They get transported from bannana plantations along the East Coast with the fruit to the supermarkets, which felt sorry for the frogs and released them in a dam nearby and they have established themselves quite well, which is not a good thing as they don't naturally occur here.


Then i looked closer at the other 'Arum Lily Reed Frog', i noticed faint spots, but its colouring was quite different to the previous one. The first picture of the post is an Arum Lily Reed Frog, but then what is this:


Is it a faintly marked individual of Painted Reed Frog? Or is it possibly a Hybrid? This could really threaten our Arum Lily Reed Frog by hybridising with it or just outcompeting it, i believe a study is happening on it.
I really don't know if that is a hybrid at all, but just thought it might be interesting...

[Mongoose]

Interesting bro.

One question though, why are you not at school!?

[arcadies]

interesting, how easily do frogs/toads hybridize though?

@goose: cause looking at frogs is more educational?

[Mongoose]

Wait till he starts looking at girls!

[alexander]

Lol, the question should be, why am i not studing for my exams.
arcadies: i have no idea

[arcadies]

Wait till he starts looking at girls!

That should be around the same time you can talk to girls without blushing. hey?

@alex: go get an edumaction, go learn you a book.

[BushSnake]

LOL.

Very interesting Alex. Painted Reed frogs are known to vary a lot, so I wouldn't jump to conclusions yet. However, better catch the culprits earlier than later. Just a question, isn't there any other characteristic, apart from colour, that is used to differentiate between the two species?

[fredsmith]

What are the implications to the local ecosystem due to the foreigner?
If there is a hybrid hopping around, whats the damage it can cause?

[alexander]

Lol, too me they look almost the same without colour, i'll ask one of the experts.
Fredsmith-they are quite similar and are likely to fill the same niche in their envronments, so they may compete for food, habitat ect.
Hybrids, If they produce viable offspring (hasn't been proven yet), they could be more succesfull or just steal mates from the "pure" Arums. It would mean in a bad situation that Arum's would go extinct and what would be left would be a population of hybrids.
But i doubt that is a hybrid, will check though.

[fredsmith]

Interesting none the less.
Thanks Alexander

[alexander]

My father emailed some experts a while back, excuse the order if i got it wrong...


>>> Tony Rebelo 2008/10/08 09:39 >>>
Hi

Am doing a course on aliens and want to mention the PRF.

Any progress on whether it:
1. Actively outcompetes Arum Lily Frog
2. Hybridizes with it
3. Spreads outside of release sites into areas where ALF present

Most relevant: how can one easily tell the two apart. A simple feature for Joe Soap.

Ta
Tony


Hi Tony,
Im attaching a pdf of some work we published. To answer your questions....

1. no body knows yet
2. dont know yet
3. I believe it does but Sarah Davies has the data on where. I have never seen the two in the same site myself. Noorhoek wetland was the only site I knew about, but from what I can gather, marmoratus is now absent from there for the last 3 years.

does that help? email Sarah about question 3....


>>> "Davies, SJ, Ms <sdavies@sun.ac.za>" <sdavies@sun.ac.za> 2008/10/08 11:17 >>>
Hi Tony
H. marmoratus certainly does spread from release sites. At present I have over 200 records from outside the natural range - too many and too scattered and strangely distributed to all be independent introductions. I am busy analysing the data to work out what the mechanisms behind the expansion might be. It is likely to be closely linked to human-mediated long distance dispersal.
Krystal is correct in saying that we have not yet found H. marmoratus and H. horstickii together (in the same water body). This remains to be investigated and will be part of my PhD study.
I would guess that hybridisation is unlikely, since there is evidence that the two species have been separate for some time (Wieczorek et al. J. Biogeog. 2000), but once again we don't know for sure.
Regards
Sarah

________________________________

From: Krystal Tolley [mailto:Tolley@sanbi.org]
Sent: Wed 2008/10/08 10:09 AM
To: John Measey; Tony Rebelo
Cc: Sarah Davies
Subject: Re: Painted Reed Frog

>>> Krystal Tolley 2008/10/08 12:00 >>>

oh yes and one more thing... they have different calls so probably wont be likely to hybridize unless they are extremely desperate for a mate. And.. the breeding seasons barely overlap. I would guess: horstockii now Oct -Dec, and marms only later Nov-Feb... but Sarah might have better info on breeding seasons.

>>> Tony Rebelo 2008/10/08 12:21 >>>
Hi Krystal and Sarah

Great: many thanks. That is perfect for my purposes.

I have pictures thanks Sarah from the web and pdf. You have not by any chance yet produced a poster alerting the public to the problem and asking for help? If so I should really appreciate a copy.

An afterthought: the difference between breeding season: this sounds like a winter - summer dichotomy: any sign that marms breed earlier (a month or two, or later 9-10 months say) further west - or are these the Western Cape breeding times? Also, "barely" is a Matter of opinion: 2 out of 3 months = 67% overlap for horstockii!

Ta
Tony
PS: my experience is that females who dont get enough sex get desperate! Even applies in plants - isolated plants are good places to look for hybrid seeds.
It is in my humble opinion a major human evolutionary flaw that most females dont need nearly as much sex as males do, and especially not after a couple of kids. If it was not for the paycheck fathers would be totally superfluous.

[Bushviper]

So from the above it would seem there is no scientific reasearch confirming that these hybridise. Maybe you should collect some (with the relevant permits of course) and have the dna tested.

[Iggy]

just a thought re your question as to the latter photos - the painted reed frogs which occur here in Hazyview (striped form rather than spotted) become extremely pale when they are sunning themselves, taking on an almost "silver" colouration - and then return to the normal bright colouration when no longer basking...so I would think your "pale version" may be the same phenomenon? I actually thought we had two colour variations til I saw the same frog in both colourations and Damien explained to me that they change colour during basking...

[alexander]

We probaly will take DNA sometime from our area, this has been done in other areas i believe-but this was to find out which sub-species of marmoratus it was.

Yes i did notice that, it turned much darker later but the patterning still remained very faint, but apparently there is a common form that occurs through the whole range of the Reed Frogs which has reduced patterning, which is browner when not exposed to too much light. I was thinking of taking pics of both of them in the light and then in the shadow, i'll try it sometime.